Emerald tree monitor

Common Name: Emerald tree monitor

Scientific Name: Varanus prasinus

The emerald tree monitor has long toes, extraordinarily sharp claws and feet covered in large scales specialised for gripping while climbing. Their tails which they use for support and climbing, are prehensile, and can grow to 1.75 times their body length.

The young are born looking identical to the adults, only smaller in size. Males and females are the same size when they first hatch but after a period of rapid growth females often stop or slow their growth whilst males continue to grow for months after. This results in the males being significantly larger than the females.

Found in humid, tropical environments, emerald tree monitors obtain most of their water from the air around them and remain in the trees even to lay their eggs.

Fast Facts

  • Status

    Least concern

  • Size

    67 cm female length 114 cm male length

  • Weight

    300 g

  • Gestation

    165 days

  • Young

    2 to 4

  • Life span

    up to 15 years in captivity

In the wild

Emerald tree monitors are primarily insectivores eating small invertebrates including katydids, grasshoppers centipedes, and spiders. They have, however, also been observed preying on small arboreal or semi-arboreal mammals such as rats.

Emerald tree monitors are arboreal reptiles, which means that they spend all their time in the trees. Their preferred habitat is rainforest, mangrove, and cocoa plantations in tropical lowland environments; ranging from the Torres Strait to islands adjacent to New Guinea.

Emerald tree monitors reach maturity at around 2 years from which time they can produce up to 3 clutches of eggs per year. Male emerald tree monitors have been observed displaying aggressive courtship behaviours after which mating occurs. Females lay 2-4 eggs after which there is no parental input.


In order to protect their eggs and young in those vulnerable early stages, females lay their eggs in arboreal termite nests, which not only offer a warm and humid environment for incubation but also provide a convenient food source for the lizards once they hatch. Hatchlings grow quickly, quadrupling in size in their first three months!

Emerald tree monitors are considered the apex predators in their habitats, as no species preys on a fully grown adult. However, snakes and birds will eat their eggs and hatchlings. Prized for their looks, they are sometimes victims of illegal poaching for the international pet trade.

Emerald tree monitors are protected under Appendix II of the Convention on International Trade in Endangered Species (CITES) providing some protection from the international pet trade. Currently, the biggest threat to these lizards is localised habitat loss, but as the emerald tree monitor is widespread and breed well in captivity, there are no specific conservation actions needed at this time.

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